The present invention relates to a system for guidance to the emergency exit in a building.
The object of the invention is to provide a system of the kind indicated above, that provides reliable guidance also in very heavily smoke filled spaces and that cannot be put out of operation by any type of cable fault, voltage interruption or the like.
The system according to the invention includes at least one flashable light located on a low level above the floor. A drive unit associated with the flashable light includes a trigger circuit and accumulator batteries. Means for detecting interruption of the supply voltage are also included. Suitably the level of the flashable lights above floor is 70 cm at most. Preferably two flashable lights are located on each side of an emergency door exit quite close to the floor. These flashable lights preferably have a drive unit in common.
The invention has the following advantages. In case of fire always the upper portion of a room is first filled with smoke, this fact forming the basis of the advice that one should try to leave a room that is filled with smoke by crawling. This, however, also implies that conventional emergency exit indication devices which are located above the emergency exit become invisible relatively fast due to the thickening smoke so that accordingly the emergency exit becomes difficult to find. If, in accordance with the invention, the flashable lights are located near the floor on each side of the emergency exit this problem is eliminated. Furthermore, the system according to the invention cannot be put out of operation in case of intermittent or complete interruption of the supply voltage since the drive unit includes a means for sensing such interruption and actuates the trigger circuit to automatically start the flashable light. The same effect is attained upon short circuiting of the voltage supply. Alarm signals from fire and smoke detectors can be fed to the drive unit by controlling the interruption of power on the supply leads, or on a separate signal wire.